How Effective Are Prescription Weight-Loss Drugs?

Compared with placebo, all treatments achieved at least a 5% weight loss at 52 weeks

HealthDay News — Any of the prescription weight-loss drugs on the market can help obese adults lose weight, although some appear to be more effective than others, according to research published in the June 14 issue of the Journal of the American Medical Association.

Siddharth Singh, MD, assistant clinical professor at the University of California, San Diego, and colleagues analyzed findings from 28 clinical trials testing the 5 approved drugs for obesity: phentermine-topiramate (Qsymia), liraglutide (Saxenda) and orlistat (Xenical), along with lorcaserin (Belviq) and naltrexone-bupropion (Contrave).

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On average, the researchers found, each drug worked better than a placebo in helping obese adults lose weight over a year. Patients on phentermine-topiramate typically lost the most weight (8.8 kg) versus study patients taking placebo. Patients taking orlistat or lorcaserin tended to lose the least amount (2.6 and 3.2 kg, respectively) versus placebo users. Naltrexone-bupropion and liraglutide patients typically lost 5.0 and 5.3 kg more, compared with placebo. Patients taking naltrexone-bupropion or liraglutide were the most likely to quit a trial over side effects, compared with placebo users (odds ratios, 2.64 and 2.95, respectively).

"Among overweight or obese adults, orlistat, lorcaserin, naltrexone-bupropion, phentermine-topiramate, and liraglutide, compared with placebo, were each associated with achieving at least 5% weight loss at 52 weeks," the authors conclude.

Several authors disclosed financial ties to the pharmaceutical industry.